36 research outputs found

    Carbon, nitrogen, and phosphorus stoichiometry and eutrophication in River Thames tributaries, UK

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    Primary productivity in aquatic systems relies on carbon (C), nitrogen (N), and phosphorus (P) availability, with a reference stoichiometric ratio of 106 C/16 N/1 P, known as the Redfield ratio. This paper presents a methodology to visualize river water C/N/P stoichiometry and examine phytoplankton response. Redfield total dissolved C/N/P concentration ratios (TDC/TDNR/TDPR) from five River Thames tributaries were plotted in a ternary diagram, allowing relationships between nutrient stoichiometry, total P concentrations, and chlorophyll a, as a surrogate for phytoplankton biomass, to be explored. Chlorophyll a concentrations above 100 μg L−1 were not observed below 14% TDPR, and concentrations above 30 μg L−1 were not observed below 13% TDPR. This indicates a potentially lower TDPR limit for highly eutrophic waters. These rivers are C and N rich, and this methodology should be applied to a wider range of rivers to explore C, N and P thresholds across different river typologies

    Applications of pseudospark produced electron beams in backward wave oscillators

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    Pseudospark electron beams have been studied recently with their application to millimetre-wave and terahertz radiation generation. To this end, backward wave oscillators (BWO), a form of vacuum tube which utilises the interaction between an axial electron beam and a slow-wave structure has been designed and modelled using the particle-in-cell code MAGIC and VORPAL. Millimetre radiation has been generated from a BWO driven by a 14-gap pseudospark discharge. The investigation of a higher frequency BWO at 200 GHz will also be presented

    Tocilizumab in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

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    Background: In this study, we aimed to evaluate the effects of tocilizumab in adult patients admitted to hospital with COVID-19 with both hypoxia and systemic inflammation. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. Those trial participants with hypoxia (oxygen saturation <92% on air or requiring oxygen therapy) and evidence of systemic inflammation (C-reactive protein ≥75 mg/L) were eligible for random assignment in a 1:1 ratio to usual standard of care alone versus usual standard of care plus tocilizumab at a dose of 400 mg–800 mg (depending on weight) given intravenously. A second dose could be given 12–24 h later if the patient's condition had not improved. The primary outcome was 28-day mortality, assessed in the intention-to-treat population. The trial is registered with ISRCTN (50189673) and ClinicalTrials.gov (NCT04381936). Findings: Between April 23, 2020, and Jan 24, 2021, 4116 adults of 21 550 patients enrolled into the RECOVERY trial were included in the assessment of tocilizumab, including 3385 (82%) patients receiving systemic corticosteroids. Overall, 621 (31%) of the 2022 patients allocated tocilizumab and 729 (35%) of the 2094 patients allocated to usual care died within 28 days (rate ratio 0·85; 95% CI 0·76–0·94; p=0·0028). Consistent results were seen in all prespecified subgroups of patients, including those receiving systemic corticosteroids. Patients allocated to tocilizumab were more likely to be discharged from hospital within 28 days (57% vs 50%; rate ratio 1·22; 1·12–1·33; p<0·0001). Among those not receiving invasive mechanical ventilation at baseline, patients allocated tocilizumab were less likely to reach the composite endpoint of invasive mechanical ventilation or death (35% vs 42%; risk ratio 0·84; 95% CI 0·77–0·92; p<0·0001). Interpretation: In hospitalised COVID-19 patients with hypoxia and systemic inflammation, tocilizumab improved survival and other clinical outcomes. These benefits were seen regardless of the amount of respiratory support and were additional to the benefits of systemic corticosteroids. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research

    Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

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    Background: Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings: Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79). Interpretation: In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research

    Whole-genome sequencing reveals host factors underlying critical COVID-19

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    Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

    Scotland–Finland Precambrian correlations

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    Isotopic age determinations indicate the generally co-eval nature of major episodes of earth history shown by the Precambrian rocks of Scotland and Finland, viz. (1) the c. 2 800—2 600 m.y. Scourian and Presvecokarelidic episodes, (2) the c. 2 200 m.y. Inverian episode and the c. 2 300 m.y. episode in Finland, (3) the c. 2.1 b.y. deposition of the Loch Maree Group in Scotland and the Jatulian quartzite, Karelian schists and related geosynclinal deposits in Finland, and (4) the c. 1 975—1 700 m.y. Laxfordian and Svecokarelian episodes. The existence of spatially connected belts in Precambrian times is suggested by the correspondence in both the sequence of development and the orientations of structural elements resulting from polyphase deformation in the successively formed Precambrian orogenic belts. This matching of complex structural frameworks implies that, before the initiation of the British-Scandinavian Caledonides, the Baltic Shield extended westward to include northwestern Britain and the continental shelf of the eastern North Atlantic Ocean. The Caledonian belt would then have developed on a plate of continental crust, or between the separated parts of a rifted continental crustal segment

    Metamorphic development of cordierite-bearing layered schist and mica schist in the vicinity of Savonranta, eastern Finland

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    The sequential development of minerals in polyphase deformed schists of the Savonranta district can be demonstrated in a limited number of lithologies. Cordierite- bearing and micaceous schists are used to established a polymetamorphic history within an area where field mapping and structural studies have provided a basis for the erection of temporal relations of metamorphic fabric elements. Coexisting phases whose relative times of development have been established were selected for microprobe analysis and their compositions used in a quantitative thermodynamic study to determine temperatures and pressures of successive metamorphic events. Conditions deduced for the phase of metamorphism (M1) associated with the D1 deformational phase are c. 550°C and 3 kb. The peak of metamorphism, during M2‒D2 was at c. 700°C and 7.5 kb. Conditions for an M3 metamorphic event of c. 300°C and 2‒3 kb are estimated from mineral assemblages in P‒T space, not from mineral compositions. A late thermal event (ML') is related to the emplacement of porphyritic granite: c. 600°C and 4kb are estimated from mineral assemblages in P‒T space. A single outcrop of a layered schist, which is unique to the district, is interpreted as a tectonic slice from a deeper crustal level. It provides evidence of a low P, high T granulite facies metamorphic event (MEARLY) pre-dating M1‒D1

    Lewisian complex of Strath Dionard-Rhiconich and its significance in the early history of the NW Highlands of Scotland

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    Metamorphosed and deformed pillows from Losomäki: evidence of sub-aqueous volcanism in the Outokumpu association, eastern Finland

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    Pillow lavas, some highly deformed and now seen as banded diopside amphibolites and tremolite-epidote-chlorite rocks (»barren skarn»), occur within the lower Proterozoic Outokumpu rock association at Losomäki, 50 km N.W. of Outokumpu. The occurrence of these sub-aqueous volcanic assemblages, together with the previously described serpentinite—metadolomite—non-detrital quartzite—cupriferous sulphide ore—black schist assemblage, is similar to those found in both Phanerozoic ophiolite complexes and the lower members of Archaean greenstone belts. The nature of this assemblage is of significance in assessing the lithospheric processes operative in early Proterozoic times as well as in elucidating the evolution of the Svecokarelides
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